Silicon based in-situ measurement system for flex loads on MLCCs in PCB manufacturing chain

A new in-situ monitoring method of mechanical loads acting on MLCC (multi layer ceramic capacitors) devices during the PCB manufacturing chain is presented in this paper. A S3MD (stress sensitive surface mounted device) is designed as a silicon based package equivalent with strain sensitive pattern for an 0805 SMD chip device. Metal thin film resistors of Cu55Ni45 and Ni65Cr35 are used as resistive strain sensitive elements. A solderable termination is created to get the solder mounting option. Bending tests like descripted in AEC Q200 “Board Flex” were done to obtain the load limits for different MLCC termination types. Therefore a suitable PCB is designed with 4-terminal-sensing. Different bending speeds are performed to characterize the possibility to analyze creeping behavior of the solder or adhesive joint with the S3MD sensor elements. Finally a depaneling process with rotary blade is performed with an in-situ measurement of the load intensity acting on the devices during the process depending on the cutting edge distance.